Process of manufacturing magnetic deflection yokes



Jan. 2, 1962 J. MARLEY 3,015,152

PROCESS OF MANUFACTURING MAGNETIC DEFLECTION YOKES Filed Aug. 23, 1955 3Sheets-Sheet 1 J- MARLEY Jan. 2, 1962 PROCESS OF MANUFACTURING MAGNETICDEFLECTION YOKES Filed Aug. 23, 1955 3 Sheets-Sheet 2 Illllll Jan. 2,1962 J. MARLEY 3,015,152

PROCESS OF MANUFACTURING MAGNETIC DEFLECTION YOKES Filed Aug. 23, 1955 3Sheets-Sheet 3 United States Pate 3,015,152 PROCESS OF MANUFACTURINGMAGNETIC DEFLECTION YOKES John Marley, Roslyn Heights, N.Y., assignor toHazeltine Research, Inc., Chicago. Ill, a corporation of Illinois FiledAug. 23, 1355, Ser. No. 530,029 19 Claims. (Q1. 29-45557) General Thisinvention is directed to a method of manufacturing electron-beamdeflection yokes utilized to effect lateral motion of beams of electronsor similar electrical particles and is particularly directed to a methodof manufacturing magnetic deflection yokes of this type. These yokes areparticularly useful for deflecting the electron beams in cathode-raytubes of the types conventionally employed in oscilloscopes, targetindicators, and most commonly used in television receivers. To a largedegree the stringency of the requirements of deflection yokes determinesthe methods of manufacturing these yokes. Since television deflectionyokes have the most exacting requirements, the process of manufacturingsuch a yoke will be described herein. However, it should be understoodthat themethod of manufacturing deflection yokes in accordance with thepresent invention may be employed in other than the manufacture oftelevision yokes.

The fundamental principles underlying television transmission andreception and the details of the apparatus employed are so well known itis deemed unnecessary for the purpose of the present invention todescribe a complete'transmitter or receiver. It is well known in the artto employ cathode-ray tubes of various forms in conventional televisionreceivers to reproduce televised images. To effect such reproduction,the cathode-ray tubes include means for emitting an electron beam whichis intensity modulated by video-frequency information. This beam isfocused into an extremely narrow beam to provide the high definitionrequired in reproducing the televised image and is deflected in twoorthogonal directions to scan a rectangular raster on the image screenof the picture tube to provide a two-dimensional reproduced image.Focusing of the electron beamis ordinarily accomplished by providingnonuniform magnetic or electric fields of regular configuration in thespace traversed by the electron beam between the' cathode and the imagescreen. Deflection of the focused electron beam is effected bydeveloping varying electric or magnetic fields in the space traversed bythe beam between the point of focusing and the image screen. The presentinvention is directed to deflection yokes for developing suchvarying'magnetic deflection fields.

\AS is well known, a beam of electronspassing through a magnetic fieldis deflected in a direction perpendicular to the instantaneous directionof motion of the electrons in the beam and to the lines of magneticforce out by the beam. In order to effect continuous and uniformdeflection of the beam in the horizontal and vertical directions, theintensities of the components of the magnetic field in these'twodirections are varied, usually by employing separate coils of complexconfigurations with their axes mutually perpendicular in which themagnitudes of the currents in the separate coils are variedindependently to provide mutually perpendicular fields.

Progressive advancements in the art of television have imposed ratherstringent requirements upon deflection yokes. A deflection yoke shouldbe an eflicient power converter, provide linear scanning, developuniform deflection fields which do not cause defocusing, and be freefrom resonant ringing and from undesired interaction of the vertical andhorizontal fields. In addition, the yoke should be inexpensive and thereshould be a high degree vWind coils which are consistently the same.

of consistency between the deflection fields developed by yokes of thesame construction. With the advent of the wide-angle picture tubeshaving deflection angles approachirig 90 and having an extremely shortneck portion it has become diflicult to satisfy these requirements.

It has been conventional to utilize saddle yokes, so called because ofthe saddle-like configuration of each of the four coils which combine toform the yoke. Because of the complex configuration of these'coils,saddle yokes require complex winding apparatus which individually windseach of the four coils and which in spite of its complexity fails tomaintain a uniform or any other desired spatial relationship of theturns in each coil or to After the winding process, the coils usuallyrequire additional shaping by manual or mechanical means to assume thesaddle form. The latter operation. introduces additional inconsistenciesbetween coils and additional irregularities within each coil. Four coilsso formed are then nested with a winding of one coil in the cavity orwindow of another to provide the complete deflection yoke. The latterassembly operation introduces additional characteristics between yokesof the same type. As a result of the above-mentioned factors, saddle"yokes have field irregularities anda lack of consistency in fieldsdeveloped by yokes of the same type. To compensate for the fieldirregularities and the variations between fields developed by differentcoils of the same type, only a small segment at the center of the fieldpattern developed by a yoke is used for deflection. The inner surfacesof the coils forming the yoke are spaced from the neck of the tube inorder to minimize the effects of field irregularities which arestrongest in the vicinity of the coil surfaces. Since only a relativelysmall portion of the total field developed by a yoke is employed,conventional saddle yokes tend to be expensive, large, and heavy, andthey develop deflection fields which are lessunifor'm than is desiredand which fail to provide the degree of control of deflection of thebeam required for best reproduction of the image. The present methods ofphysically winding Wire into complex coil forms and then assembling thecomplex coils into a saddle yoke make the elimination of theabovedescribed undesired factors extremely diflicult. Therefore, it isdesirable to practice new methods of manufacturing deflection yokes.

i It is, therefore, an object of the present invention. to provide amethod of manufacturing deflection yokes which do not have thedeficiencies and limitations of prior yokes.

. It is an additional object of the present invention to provide amethod of manufacturing deflection yokes utilizing printed wiringtechniques.

It is still another object of the present invention to provide a methodof manufacturing deflection yokes which is easily and simply practicedto provide yokes with constant magnetic characteristics.

It is a further object of the present invention toprovide a method ofmanufacturing deflection yokes in which a plurality of windings arepreformed in fixed spatial relationship.

It is a further object of the present invention to provide a new andimproved deflection yoke which does not have the deficienc es andlimitations of prior yokes.

It is a further object of the present invention to pro vide a simple andinexpensive deflection yoke with uniform magnetic characteristicsutilizing printed wiring techniques.

3 ping the elongated sides of the coil around a yoke core wall in suchmanner that the elongated sides of the coil encircle the core wall toform two deflection windings in different radial quadrants of the core.

Further in accordance with the present invention, a cathode-ray tubedeflection yoke comprises a yoke core and a dielectric sheet bearing acontinuous loop-type conductor pattern surrounding a wall of the yokecore so that the two coils formed by the two sides of the looptypeconductor pattern fall in radial quadrants of the core.

Referring to the drawings:

FIG. 1 is a perspective view of a deflection yoke in accordance with thepresent invention mounted on the neck of a cathode-ray tube shown infragmentary form;

FIG. 2 is a front elevation view of the yoke of FIG. 1, with a portioncut away toshow interior detail;

FIG. 3 is a plan view of a strip of dielectric material including one ofthe coils utilized in the yoke of FIGS. 1 and 2; and

FIG. 4 is a plan view of a strip of dielectric material including amodified form of coil winding.

Description of deflection yoke In FIG. 1 a perspective view of adeflection yoke manufactured in accordance with the present invention isshown mounted on the neck of a cathode-ray tube 11 which may be, forexample, the picture tube of a television receiver. The yoke 10 is acircularin cross section and preferably fits closely around the neck ofthe tube 11 with one end of the yoke, more specifically the beamexitend, extending over at least a small length of the flared portion of thetube 11. The .yoke 10 includes four complete coils 12-1'5, inclusive,which are identical in shape and form but which differ in size and maydiffer in the size or number of conductors. Each of these coilssurrounds 180 of the surface of a ring core 16. For example, asrepresented in FIG. 2, the coil 12 occupies the first and fourthquadrants, the coil 13 the second and third, the coil 14 the first andsecond, and the coil 15 the third and fourth quadrants of the. circleformed by the core 16. As is apparent from the drawing, the dimensionsof the coils 1.4 and 1.5 are such that they may be placed within theouter coils 12 and 13.

Each of the coils 1215, inclusive, is supported on a dielectric sheetand, when in their assembled form as shown in FIG. 1, each includes apair of distinct, though interconnected, windings. Referring to FIGS. 1and 2, the coil 12, for example, has a pair of distinct windings 12a and12b. These windings are shown in FIG. 3 in more detail and in unfoldedform. The two distinct windings result when the dielectric sheet 17 ofFIG. 3 is rolled up around, for example, the end turns 12d, the winding12a being formed by the rolled-up side 120, while the winding 12b isformed by the rolled-up side 1'2b. It is apparent that these twowindings are interconnected by the end turns 12c and 12d.

The coils 12-15, inclusive, are so disposed with respect to each otheraround the neck of the tube as to develop mutually perpendicularmagnetic axes to effect horizontal and vertical deflection of the beamin the tube. For example, assuming the coils 12 and 13 having windings12a, 12b and 13a, 13b develop the vertical deflection field, thenwindings 14a, 14b and 15a, 15b of coils 14 and 15, respectively, areutilized to develop the horizontal deflection field. Each of the coilwindings such as, for example, the winding 12a of coil 12 occupiesapproximately 60 of the circumference of the ring core 16, the windings12a, 12b and 13a, 13b individually overlapping portions of the windings14a, 14b and 15a, 1511.

Referring now to FIG. 3, each of the coils 12-15, inclusive, asrepresented by coil 12 in FIG. 3, is supported on a sheet of dielectricmaterial 17 and has rectangularly disposed fiat ends corresponding tothe ends 120 and 12d as well as flat sides corresponding to the sides12a and 12b. By fiat is meant that the ends and sides of the coil layflat against the surface of the dielectric sheet 17.

The sides of these coils, as represented by the sides 12a and 12b inFIG. 3, have alternate beam-deflection sections 18 and current-returnsections 19 connected by alternate flaring and converging sections 20.For the form of coil construction shown in FIG. 3, the beam-deflectionsections 18 are relatively narrow in the vertical dimension of thedrawing, while the current-return sections 19 are relatively widesections. This configuration is desirable so that the conductors of theflaring and converging sections 20, which form the end turns of theassembled structure, will fan out radially from the cathode-ray tubeaxis. It will be noted that the coil 12, when viewed in its unfoldedform as shown in FIG. 3, is a continuous coil Winding having a pluralityof elongated rectangular-like turns which progress in a spiral-likemanner towards the center region of the unfolded coil winding.

The conductors in each of the coils 12-15, inclusive, are formed byemploying printed circuit techniques and are, for example, approximately15 mils wide, 1.5 mils thick, and are separated from each other byapproxi mately 15 mils. For simplicity of representation, in FIGS. 1 and3 only a few conductors have been shown representing each of thewindings and the relative conductor sizes and spacings are not to scale.In practice, the density of the conductors as well as the total numberand size of the conductors is control-led by the field strength desired.The pattern of the spacings of the conductors is determined by the fieldpattern desired. For example, if a cosine field pattern is needed tocorrect for such problems as pin-cushion or barrel distortion, then thewindings are spaced or have distributed density according to a cosinepattern.

The side windings 12a and 12b, specifically the narrow sections 18 ofthese windings, provide the deflection energy for deflecting thecathode-ray-tube beam, the wide, flaring, and converging sections 19 and20 serving only to complete the current path for the narrow sections.The center portion of the dielectric sheet may be omitted when the sheetis manufactured or may be cut out before or after the conductors havebeen formed on the sheet,- thus, leaving an open region 21 as shown inFIG. 3. In addition, slits, represented by the dashed lines in FIG. 3,are made between conductors in the converging and flaring sections 20 tofacilitate the winding of the sheet of conductors into a tubular formand the bending of the tube to fit over an arc of the core 16. Thelengths of the different sections in the coil sides are madeprogressively longer. That is, for example, the length of the secondnarrow section counting from the end 12d in a coil side such as side1212 is longer than that of the first, and the third is longer than thatof the second. The difference in length is determined by the thicknessof the dielectric sheet resulting in the successive circumferences ofthe layers of the sheet when wound in tubular form becomingprogressively larger.

A group of coils of the type represented by FIG. 3, after each has beenrolled into a flattened or rectangular tube about an axis parallel tothe coil ends, for example, the ends and 12d, are combined on the ringcore 16 in the order represented in FIG. 1 to provide a completedeflection yoke. The core 16 may be, for example, of ferromagneticmaterial such as ferrite in order to provide a low reluctance returnpath for the magnetic flux developed by the coils and preferably isseparable into quadrant pieces to facilitate the threading of thetubular coil structure onto the core in the desired order. The coilsenclose the walls of the core and the coil sides 12a and 12b areparallel to the axis of the core. The beamdeflection or narrow sections18 of the coil sides are superposed on the inner and the wide orcurrent-return sections 19 superposed on the outer walls of the core 16.The coils are secured about the circumference of the core, after beingadjusted in proper spatial relationship, by means of an adhesive on thecore or by adhesive tape.

Method of manufacturing deflection yoke The process of manufacturing adeflection yoke in accordance with the present invention commences withthe preparation of an elongated rectangular-like coil winding such asrepresented by FIG. 3 on each of a plurality of dielectric sheets. Thesesheets may be, for example, of some thin flexible plastic material suchas vinylite or a phenolic Fiberglas and are either of a rectangularshape including a center portion or of similar shape without the centerportion. By means of conventional printed wiring processes a coil, forexample coil 12 having sides 12a and 12b and ends 12c and 12d, and inwhich the sides have alternate wide and narrow sections connected byalternate flaring and converging sections, is formed on each dielectricsheet. The printing process may, for example, comprise etching theconductors for each coil out of a thin copper plating coating thedielectric sheet, conventionally known as copper-clad. Alternatively,each coil may be impressed or sprayed onto the dielectric sheet to formcopper, silver, or other conductive material. Conventional printing orspraying processes can be employed. In forming the coils on thedielectric sheet, each set of four sections of a coil, for example thesections including a wide, a narrow, a flaring, and a convergingportion, is made progressively longer to compensate for the additionalcircumference in each coil layer of four sections. The lengths of thefirst four sections are determined by the length of the first narrowsection and the thickness of the core. The length of the first narrowsection is determined by the deflection force desired and is limited bythe available length on the neck of the picture tube. Each coil is onecontinuous loop of conductors having terminals as indicated by thereference letters T and T in FIG. 3. If desired, slits, as representedby the dashed lines, are cut or otherwise formed between the conductorsin the flaring and converging sections to facilitate the forming of thedielectric sheet and the coil thereon into a flattened tube. It slitsare provided they should be slightly longer than the flaring andconverging sections, but not so long as to disturb the fixed spacing ofat least the conductors in each narrow section.

Each sheet so prepared is rolled on a mandrel or by other means about anaxis parallel to the ends of the coil so that the coil sides are normalto this axis and form rings at the ends of the tube formed by the sheet.The folding process is such that corresponding sections in each side, aswell as the two end sections, are superposed. In other words, each layerin the flattened tube includes a set of the four coil sections with, forexample, all of the beam-deflection or narrow sections 18 in thedifferent layers superposed. For coils 14 and 15, the interiordimensions of the tubes formed by the coils are approximately equal tothe outside dimensions of the core 16. Coils 12 and 13 form tubes inwhich the internal dimensions are approximately equal to the outsidedimensions of the coils 14 and 15. In view of the difference in size ofthe tubes formed by the different coils, coils 12 and 13 have longersides and each of the sections in each side is correspondingly longerthan the sides and the sections of coils 14 and 15.

As previously mentioned, the core 16 is preferably broken into fourquadrant pieces having irregular rather than machined mating edges. Theirregular mating edges of adjacent pieces provide greater contactsurfaces thereby decreasing interface effects. On quadrant of the core16 is threaded through the internal openings in the tubes formedby thecoils 14 and 12 in the order mentioned to provide the upper right-handor first quadrant of the yoke of FIGS. 1 and 2. In a similar manner thesecond quadrant of the core 16 is threaded through the tubes formed bycoils 14 and 13, the third quadrant through the tubes formed by coilsand 13, and the fourth quadrant through the tubes formed by coils 15 and12 in that order.

The quadrant sections of the .core are:

then fitted together to form the cylindrical or ring core 16 and aresecured in that position by use of adhesive or by tape which secures thedifferent coils in proper position. A dust cover (not shown) and amagnetic shield (not shown) may be added to enclose and protect thecoils. In addition, considering FIG. 3, not all of the end turns at endsand 12d need cross over at the very ends. Some may cross over atintermediate points to delete the total number of turns per layer ofcoil as the layers build up. This saves cost and space with little lossin magnetic flux.

Modified coil structure of FIG. 4

Referring now to FIG. 4 of the drawings, there is shown an alternativeform of conductor pattern that may be printed on the dielectric sheet 17and which should be mentioned in detail because of the reduced energylosses associated with a deflection yoke which utilizes such a conductorpattern. The conductor pattern as shown on the unfolded dielectric sheet17 of FIG. 4 is similar to the pattern on the unfolded dielectric sheetshown in FIG. 3 except that the current-return sections 19 on oppositesides 12a and 12b of the conductor pattern have been positioned moreclosely to one anothen The conductor pattern on the dielectric sheet 17of FIG. 4 is rolled up the same manner as previously described so as toforma flattened tubular structure which may be placed on the ring core16 of the deflection yoke. It will be apparent that when this is done,the more closely spaced current-return sections 19 will lay on top ofone another on the outside of the core 16. Now, as the current flow inthe current-return sections 19 making up the side 12a is flowing in adirection oppositie to the current flowing in the sections 19 making upthe side 12b, the magnetic fields produced by adjacent sections on thetwo sides 12a and 12b of the conductor pattern will partially cancel oneanother. This means that less energy will be stored in the magneticfields produced by the current-returnsections and, hence, the energylosses due to eddy currents, etc., will be reduced, thus resulting in amore efiicient operation of a deflection yoke utilizing such conductorpatterns.

While the conductor configuration shown in FIG. 4 indicates one mannerin which the current-return sections 19 of the coil 12 may be spacedmore closely to one anothen'it will be apparent to those skilled in theart that other configurations are possible for producing the desiredmagnetic field cancellation. Any conductor pattern wherein thecurrent-return sections on opposite sides of the conductor pattern arebrought into a closely adjacent relationship with one another willproduce the desired results.

In deflection yokes of any of the foregoing types, the conductors ineach of the coils is constrained as a result of being printed in fixedposition to have fixed and consistent spatial relationships with respectto each other. As a result, uniform coils or coils with conductorsnonuniformly distributed in any desired pattern are consistentlymanufactured. The magnetic fields developed by coils manufactured in themanner described herein are as exact and controlled in pattern asdesired and are consistently duplicated. This results in a relativelyinexpensive and light-weight deflection yoke which provides greatlyimproved deflection and has a minimum disturbing eifect on the focusingof an electron beam.

Though relatively simple deflection yokes and their manufacture havebeen described and no extensive discussion of techniques for correctingfor well-known deficiencies in yokes has been presented, it should beapparent to those skilled in the art that many of the practices whichare conventionally employed to develop magnetic field patterns ofsuitable distribution to correct for field deficiencies may equally wellbe employed in the preparation of a yoke such as described herein. Infact, the use of printed-wiring techniquesfacilitates the obtaining ofmany of these corrective effects by simplifying the grading of conductorsize and spacing of conductors in any desired manner to obtain fieldpatterns which provide the corrective effects desired.

While there have been described what are at present considered to be thepreferred embodiments of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention, and it is, therefore,aimed to cover all such changes and modifications as fall within thetrue spirit and scope of the invention.

What is claimed is:

1. The method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on an insulating base an elongated flat coil theturns of which progress continuously between the center and outerregions of the coil; and wrapping the elongated sides of the coil arounda yoke core wall in such manner that the elongated sides of the coilencircle the core wall to form two deflection windings in differentradial quadrants of the core.

2. The method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on an insulating base an elongated flat coil theturns of which progress continuously between the center and outerregions of the coil; and wrapping the elongated sides of the coil arounda yoke core wall in such a manner that the elongated sides of the coilencircle the core wall to form two deflection windings in differentradial quadrants of the core and the short ends of the coil arepositioned on the outer periphery of the core.

3. The method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on an insulating base an elongated flat coil theturns of which progress continuously between the center and outerregions of the coil; and wrapping the elongated sides of the coil arounda yoke core wall in such manner that the elongated sides of the coilencircle the core wall to form two deflection windings in differentradial quadrants of the core, and the short ends of the coil arepositioned on the outer periphery of the core in proximity to each otherso that their magnetic fields tend to cancel each other.

4. The method of manufacting a deflection yoke for a cathode-ray tubecomprising: forming on an insulating base an elongated flat coil theconductor turns of which progress continuously between the center andouter regions of the coil; and wrapping the elongated sides of the coilaround a yoke core wall in such manner that the elongated sides of thecoil encircle the core wall to form two deflection windings in differentradial quadrants of the core, adjacent conductors in the elongated sidesof the flat coil being shaped during forming with alternate narrow andwide spacing therebetween along the length of the coil side so that foreach of the resulting deflection windings the conductors inside the coreare more closely spaced to one another than the conductors outside ofthe core.

5. The method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on an insulating base an elongated flat coil theturns of which progress continuously between the center and outerregions of the coil; and wrapping the elongated sides of the coil arounda yoke core wall in such manner that the elongated sides of the coilencircle the core wall to form two deflection windings in differentradial quadrants of the core, adjacent conductors in the elongated sidesof the flat coil being shaped during forming with alternate narrow andwide spacing therebetween along the length of the coil side so that foreach of the resulting deflection windings the conductors inside the coreare more closely spaced to one another than the conductors outside ofthe core and so that those portions of the turns interconnecting theforegoing conductors are directed radially of the core so as to minimizeradial components of their magnetic field.

6. The method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on an insulating base an elongated flat coil theturns of which progress continuously between the center and outerregions of the coil; and wrapping the elongated sides of the coil arounda yoke core wall in such manner that the elon-- gated sides of the coilencircle the core wall to form two deflection windings in differentradial quadrants of the core, the opposite elongated sides of the flatcoil being shaped during forming with portions of the two sidesalternately adjacent and nonadjacent so that those portions of the turnsadjacent the outer periphery of the core for one of the resultingwindings are closely spaced to those of the other winding, wherebymagnetic fields of those portions in one winding tend to cancel magneticfields of those portions in the other winding. I

7. A method ofmanufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets acontinuous coil Winding comprising a plurality of elongatedrectangular-like turns which progress in a spiral-like manner towardsthe center region of the coil winding; rolling each of said dielectricsheets into a flattened tubular structure to form two spaced andinterconnected deflection windings securing a plurality of said tubularstructures around the walls of a yoke core so that said windings enclosethe walls of said core thereby to form a deflection yoke for acathode-ray tube.

8. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate beam-deflection and current-return sectionsconnected by alternate flaring and converging sections; rolling each ofsaid dielectric sheets into a flattened tubular structure having saidsides normal to the axis thereof and having corresponding ones of saidsections superposed; and securing a plurality of said tubular structuresaround the walls of a yoke core to form an array of coils disposed insuch manner as to enclose the walls of said core and having said coilsides parallel to the axis of said core and having said beam-deflectionsections superposed on the inner and said current-returnsectionssuperposed on the outer walls of said core.

'9. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate Wide and narrow sections connected by alternateflaring and converging sections; rolling each of said dielectric sheetsinto a flattened tubular structure having said sides normal to the axisthereof and having corresponding ones of said sections superposed; andsecuring a plurality of said tubular structures around the walls of ayoke core to form an array of coils disposed in such manner as toenclose the walls of said core and having said coil sides parallel tothe axis of said core and having said narrow sections superposed on theinner and said wide sections superposed on the outer walls of said core.is

10. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longnarrow coil having substantially rectangularly disposed flat ends andflat sides having alternate wide and narrow sections connected byalternate flaring and converging sections; rolling each of saiddielectric sheets into a flattened tubular structure having said sidesnormal to the axis thereof and having corresponding ones of saidsections superposed; and securing a plurality of said tubular structuresaround the walls of a yoke core to form an array of coils disposed insuch manner as to enclose the walls of said core and having said coilsides parallel to the axis of said core, said narrow sections superposedon the inner and said wide sections superposed on the outer walls ofsaid core, and said flaring and converging sections on the side wallsrofsaid core.

11. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having progressively longer alternate Wide and narrow sectionsconnected by progressively longer alternate flaring and convergingsections; rolling each of said dielectric sheets into a flattenedtubular structure having said sides normal to the axis thereof andhaving corresponding ones of said sections superposed; and securing aplurality of said tubular structures around the walls of a yoke core toform an array of coils disposed in such manner as to enclose the wallsof said core and having said coil sides parallel to the axis of saidcore and having said narrow sections superposed on the inne andsaid widesections superposed on the outer walls of said core.

12. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate wide and narrow sections connected by alternateflaring and converging sections; rolling each of said dielectric sheetsinto a flattened tubular structure having said sides normal to the axisthereof and having corresponding ones of said sections superposed; andsecuring a plurality of said tubular structures around the walls of aring-type yoke core of magnetic material to form an array of coilsdisposed in such manner as to enclose the walls of said core and havingsaid coil sides parallel to the axis of said core and having said narrowsections superposed on the inner and said wide sections superposed onthe outer walls of said core.

13. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate wide and narrow sections connected by alternateflaring and converging sections; rolling each of said dielectric sheetsinto a flattened tubular structure having said ends parallel and saidsides normal to the axis thereof and having corresponding ones of saidsections superposed; and securing a plurality of said tubular structuresaround the walls of a yoke core to form an array of coils disposed insuch manner as to enclose the walls of said core and having said coilsides parallel to the axis of said core and having said narrow sectionssuperposed on the inner and said wide sections superposed on the outerWalls of said core. I

14. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate wide and narrow sections connected by alternateflaring and converging sections; rolling each of said dielectric sheetsinto a flattened tubular structure having said sides normal to the axisthereof and having corresponding ones of said sections superposed; andsecuring a plurality of said tubular structures around the walls of ayoke core with the coil sides of one of said sheets overlapping thecoilsides of adjacent ones of said sheets to form an array of coilsdisposed in such manner as to enclose the walls of said core and havingsaid coil sides parallel to the axis'of said core and having said narrowsections superposed on the inner and said wide sections superposed onthe outer walls of said core.

15. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate wide and narrow sections connected by alternateflaring and converging sections and having slits between conductors insaid flaring and converging sections; rolling each of said dielectricsheets into a flattened tubular structure having said sides normal tothe axis thereof and having corresponding ones of said sectionssuperposed; and securing a plurality of said tubular structures aroundthe walls of a yoke core to form an array of coils disposed in suchmanner as to enclose the Walls of said core and having said coil sidesparallel to the axis of said core and having said narrow sectionssuperposed on the inner and said wide sections superposed on the outerwalls of said core.

16. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: printing on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and long flatside's having alternate wide and narrow sections connected by alternateflaring and converging sections; rolling each of said dielectric sheetsinto a flattened tubular structure having said sides normal to the axisthereof and having corresponding ones of said sections superposed; andsecuring a plurality of said tubular structures around the walls of ayoke core to form an array of coils disposed in such manner as toenclose the Walls of said core and having said coil sides parallel tothe axis of said core and having said narrow sections superposed on theinner and said wide sections superposed on the outer walls of said core.

17. A method of manufacturing a deflection yoke for a cathode-ray tubecomprising: forming on each of a plurality of dielectric sheets a longcoil having substantially rectangularly disposed flat ends and flatsides having alternate beam-deflection and current-return sectionsconnected by alternate flaring and converging sections, correspondingcurrent-return sections on opposite sides of the coil being formed so asto be spaced more closely to one another than the beam-deflectionsections; rolling each of said dielectric sheets into a flattenedtubular structure having said sides normal to the axis thereof andhaving corresponding ones of said sections superposed; and securing aplurality of said tubular structures around the walls of a yoke core toform an array of coils disposed in such manner as to enclose the wallsof said core and having said coil sides parallel to the axis of saidcoreand having said beam-deflection sections superposed on the inner andsaid current-return sections superposed on the outer walls of said core,the close spacing of the current-return sections affordingmagnetic-field cancellation thereby to reduce the power loss of thedeflection yoke.

18. A printed circuit element for a cathode-ray tube deflection yoke,the element comrpising: a sheet of dielectric material; and a conductorpattern aflixed to the dielectric sheet and comprising a continuousloop-type conductor pattern having two elongated sides joined by twoshort sides, the elongated sides having alternate wide and narrowsections connected by alternate flaring and converging sections.

19. A printed circuit element for a cathode-ray tube deflection yoke,the element comprising; a sheet of di-v electric material; and aconductor pattern aflixed to the dielectric sheet and comprising acontinuous loop-type conductor pattern having two elongated sides joinedby two short sides, the elongated sides having alternate sections whichare spaced nearer to and farther from one another and are connected byintervening oblique sections.

References Cited in the file of this patent UNITED STATES PATENTS 4Franz Sept. 17, 1935 ,960 Eisler May 25,v 1948 55 Combs Dec. 7, 1948 92Pearce Apr.'24, 1951 ,355 Sickles et al. Oct. 19, 1954 ,407 Sanford Oct.9, 1956 7,869 Rice Oct. 1, 1957 FOREIGN PATENTS 674, 08 British...............a June 18, 1952

